SCITUATE — For 11 years, Joe Jutras has been big into gardening. Like two tons of pumpkin big.

They sit in his backyard each autumn, like giant orange tortoises, enormous gourds surrounded by leafy vines. This year, he’s grown four. Each of them is more than 1,000 pounds, meaning between them his yard has produced about two tons of giant squash.

The king of his pumpkins is a 1,689-pound monster that set a new world record at the Topsfield Fair, in Topsfield, Mass., last Saturday. Jutras followed that up the next day by taking first at a contest in Connecticut with a 1,352 pounder. So far this season, he’s won three giant pumpkin competitions.

“I’ve had a very good year,” he says.

Tomorrow, he’ll compete in the 14th annual Southern New England Giant Pumpkin Championship, which kicks off at 10 a.m. at Frerichs Farm off Kinnicut Avenue in Warren. The weigh-off begins at 1 p.m.

Jutras has won there before, but he only expects to place in the top five this time around with one of his massive entries. Contestants can enter each pumpkin in a single contest, so he won’t be able to bring the gourd that smashed the old record of 1,502 pounds set by Coventry farmer Ron Wallace last year.

Before the weigh-in last week in Topsfield, Jutras knew he had an unusually heavy squash.

“When I put my ear on it and tap it,” he said, “I can tell if it’s a very heavy pumpkin.”

By measuring its dimensions, he estimated it came close to 1,700 pounds. At that size, it would not only break the previous record; it would obliterate it. So Jutras felt obligated to take it to the Massachusetts competition, a marquee event on the pumpkin-growing calendar that draws contestants from all over New England.

“A pumpkin that size needed to be seen by a lot of people,” Jutras said.

Pumpkins’ “bloodlines” are traced as if they were thoroughbred horses. The seeds are named by the number of pounds the source pumpkin weighed and the farmer who grew it. Jutras’ favorite this year was from a 1068 Wallace, named for a 1,068-pound pumpkin grown by Wallace, the Coventry farmer.

But his record pumpkin was grown from a seed taken from a 998 Pukas. That pumpkin was a cross between a 1446 Eaton — the heaviest pumpkin in 2005 — and a 1420 Larue — the second heaviest that year. Jutras calls the seed he got hold of “the silver bullet.”

In general, the seeds are the real prizes. Last year, seeds from the heaviest pumpkins went for between $700 and $800 each. But even at those rates, the payoffs are iffy. Sometimes you can cut open a 1,000-pounder and not find a single seed, Jutras said.

Growers will cross-breed for different genetic traits. A seed from a large pale pumpkin might be crossed with one from a lighter but more orange one. And you always look out for strains that are more resistant to fungi.

After his victory in Topsfield, Jutras expects other seeds from the 998 Pukas to fetch up to a $1,000 each. They could go for even more. Not many of the 220 seeds from that pumpkin are still available, Jutras has heard.

Pumpkins aren’t the Scituate resident’s only horticultural hobby. Peach and apple trees are in his front yard and in the backyard is an approximately 15-foot-tall arbor for growing long gourds, whose fruit drops from the roof long, straight and thin. Jutras holds the world record for the longest (10 feet, six and a half inches) ever grown. He kept it, surgically removing the seeds, gluing the cut closed and then drying it out in his basement.

But it is pumpkin titles that Jutras really wants to win. His season started in late April, when he put seeds in peat moss pots and kept them heated to 85 to 90 degrees. Once the third leaf sprouted from the shoots, Jutras could plant them in the ground. The third leaf is crucial because the vine will grow in the opposite direction from that leaf, and direction is vital to properly placing the vine.

Each vine will have about 700 square feet of garden to grow in. They will be planted at one end of the section and the main vine will be directed straight ahead about 30 feet. Any length after that will be cut off, so as not to waste growing resources. Side vines will be allowed to run out for about 12 feet on either side, creating what Jutras called the Christmas tree layout.

In early July, Jutras took a male flower from one vine and rubbed it in the female flower of another at three or four spots on the vine, then watched to see which of the resulting fruit showed the most promise. Two weeks after that, the winner was chosen and the other fruits were cut off. From then on, all the plant’s fruit-growing effort was channeled into one pumpkin.

If the weather is sunny and hot, giant pumpkins can grow as much as 35 or more pounds a day, Jutras said.

Jutras cares for his pumpkins as if they were pets. They have to be tended, weeded, watered and fed. On cold nights, he’ll put blankets on them. If they’ve been cut, from the vines, he’ll protect them from too much sun with a tent. Mouse traps are set around them to keep rodents from boring into their sides.

They are fed a special, organic compost soup of various natural bacteria, worm casings and a dash of rabbit manure. Jutras swears he can see a difference the next day.

“The next day, the leaves are all waxy,” he said, smiling. “Those leaves are loving that stuff.”

“It’s his baby, don’t let him kid you,” Jutras’ wife Susan said.

“It’s a fine line between pushing the thing too far or not enough,” he said. “If you’re not careful, you’ll just blow them up.”

akuffner@projo.com